A as in Aisle
B as in Bdellium (the b is silent)
C as in Czar
D as in Djinn
E as in Eye
F as in Felinfoel (Welsh town, pronounced Velinfoe)
G as in Gnat
H as in Hour
I as in Irk (or Ian)
J as in Junta
K as in Know
L as in Llullaillaco (South American volcano pronounced Yu.Yai.Ya.ko)
M as in Mnemonic
N as in Ndebele
O as in One (or indeed Oestrogen or Ouija)
P as in Pneumatic (or indeed phonetic)
Q as in Quay
R as in Rzeznik (the polish pronunciation has a silent R)
S as in Szilard (or Sgraffitto)
T as in Tzar (it is an added bonus to have one word that represents two letters but if you think that might be confusing somehow you can use Tsunami instead)
U as in Urn
V as in Veni vidi vici (each word pronounced with a w)
W as in Whole
X as in Xhosa
Y as in Yvonne (or Ylang Ylang)
Z as in Zhivago

bonus phonetic but confusing

A as in H
D as in W
E as in F, E, M, N or X
S as in C (Sea)
W and in Y (Why)
Y as in U (You)